摘要:
An acoustically generated image includes only selected acoustical components. When an original acoustic signal interacts with an object, the resultant acoustic signal comprises a diffracted component and an undiffracted component. The acoustical images of the present invention are generated with either the diffracted component only or the undiffracted component only. In an alternative embodiment, the acoustically generated image may comprise selected frequency component(s) from the diffracted component of the acoustic signal.
摘要:
An ultrasonic signal (106) is used to link a beacon unit (101) to a tracker unit (100) to provide a tracking and navigation system for firefighters to use in a smoke filled environment at the scene of a fire. The beacon unit transmits an omnidirectional ultrasonic signal. The tracker unit, using a directional ultrasonic receiver provides a display or other indication of the signal strength of the received signal to allow the direction to the beacon unit to be determined. The ultrasonic signal provided by the beacon unit may be pulse modulated to inlcude digitally encoded data that may be used to identify particular individuals, objects, materials, dangers, or exits. In addition, the tracker unit may be provided with a transmitter and the beacon unit provided with a receiver such that audio communication may be established therebetween.
摘要:
Procédé et dispositif d'holographie acoustique utilisant un faisceau ultrasonore limité dans l'espace. La zone (29) à contrôler, contenant un défaut (28), est insonifiée au moyen d'un émetteur (22) d'ultrasons à faisceau limité dans l'espace qui est déplacé pas à pas, les signaux provenant des zones (17) successivement insonifiées sont détectés par plusieurs récepteurs (24), les phases et les amplitudes de ces signaux sont déterminées et la reconstitution de la zone à contrôler est effectuée. Elle comporte une image principale du défaut et des images parasites de celui-ci. Le nombre de récepteurs est choisi pour que la distance entre les images parasites et l'image principale soit supérieure à la largeur de la zone insonifiée par l'émetteur et la reconstitution est effectuée seulement dans les zones insonifiées ayant donné naissance à un signal, pour éliminer les images parasites. Application au contrôle non destructif de pièces mécaniques.
摘要:
A scan acoustical holographic apparatus and method for sequentially acoustically scanning the interior of an optically opaque volume (11). The apparatus includes an array of acoustic tranducers (16) that are coupled to the volume for directing acoustic signals into the volume (11) and to receive reflected acoustic signals from the volume (11 a a plurality of frequency divider means (23) receiving high frequency clock pulses and generating electrical pulse signals for transmission by the transducers (16) the phases of these signals being controlled by phase adjusting means (50) in dependence in the distances between the transducers (16) and selected focal points (A,B,C) within the volume (11) to effectively focus the transducers on the focal point and mixing means (52) for mixing the phase adjusted signals with the received signals to effectively focus the transducers (16) during a receive mode and to generate high amplitude holographic signals when the receive signals are in phase with the phase altered transmitted signals. The resultant holographic signals can be electronically processed to form an electronic analogue hologram which is utilized to visually display a holographic image of the interior of the volume (11).
摘要:
The invention relates to a method for producing a lens (2) for an ultrasound apparatus, as well as to an apparatus comprising the lens. The method comprises choosing a source point (6), providing a treatment volume (4) situated inside a bone tissue model (3), providing a plurality of nodes (5) distributed inside the treatment volume (4), and simulating the emission of a spherical wave (7) from each of the nodes (5). Thus, a simulated wave front is created, in which each spherical wave (7) has an amplitude and a phase, there being at least two nodes with different amplitudes and/or phases. The simulated wave front is received on a receiving surface (8). On the basis of the processed results, a holographic lens surface is designed, which can generate a wave pattern equivalent to the simulated wave.